🇺🇸 United States · Earthwork
Grave Creek Mound
Early Woodland, Adena culture 1000 BCE–1 CE (peak 250–150 BCE) · Adena
Largest conical burial mound in North America (62 ft/19 m high, 240 ft/73 m diameter, 60,000 tons earth moved by basket) built by Adena peoples at Moundsville, WV.